Thermoplastic container



A. STRAH M THERMOPLASTIC CONTAINER July 19, 1955 Filed Deo. 28, 1954 6 Sheets-Sheet 2 IN VENTOR ANDRE' STRAHM BMW, MW uw ATTORNEYS July 19, 1955 A. STRAHM THERMOPLASTIC CONTAINER 5 Sheets-Sheet 5 Filed Deo. 28, 1954 /o FGJI. 1*

R O T N E V m A /VDRE STRAHM BY Y @M/y LATTORIQEYfi United States Patent O THERMOPLASTIC CONTAINER Andre Strahm, Vevey, Switzerland, assigner to Uni-Tubo S. A., Vevey, Switzerland, a corporation of Switzerland Application December 2S, 1954, Serial No. 478,017

4 Claims. (Cl. 15b-0.5)

This invention relates to containers including flexible- Wall containers, such as the usual squeeze bottles and collapsible tubes which are generally made of a suitable plastic and employed for cosmetics, foods, pharmaceuticals, etc. v

The primary object of the invention is to provide a construction having improved sealing qualities and enhanced rigidity. The containers will withstand filling and handling without objectionably affecting either their general appearance or the contents.

Containers according to this invention are best made by following the methods described and claimed in my` United States Patent No. 2,673,374, March 30, 1954, and my copending applications, Serial No. 419,793, filed March 30, 1954, and Serial No. 466,919, led November 4, 1954, of which this application is a continuation-inpart.

Each of the improved containers now to be described has an integral seal between the head piece and tubular body, characterized by a vertically and circumferentally continuous fused joint area in which a narrow marginal portion of the material of the tubular body, at its top, overlies and merges with a narrow marginal portion of the material, at the lower end only of the head piece. Thereby, the union and seal between the head piece and body, regardless of their shape, are made permanent and tight in that the joint area extends continuously peripherally and also on a vertical curve, both substantially vertically and at an angle with respect to the vertical.

Stated briey, the present invention provides a container of conventional thermoplastic material, such as polyethylene, polyvinyl chloride, etc., having a tubular body and a head piece continuous with one, e. g., the upper, end of said body, a relatively narrow band portion of the inner surface of the material of the body at said end overlapping and fused with a band of equal width of the outer surface of the head piece, thereby to form a joint area which is continuous circumferentially and also vertically, and which includes both the top and side of the container at the said upper end of the same.

Referring to the drawings:

Figure l is a partial section of a mold with the head piece being formed by injection molding and the body and head piece being joined by fusing;

Figure 2 is a partial section of the container formed in Figure 1 and illustrating the joint area extending continuously both peripherally and also on a vertical curve both substantially vertically and at an angle with respect to the vertical;

Figure 3 is a partial enlarged section of the joint shown in Figure 2;

Figure 4 is a view similar to Figure 3 of a modification;

Figure 5 is a view similar to Figure l showing a modilied mold and joint;

Figure 6 is a view like Figure 2 of the container of Figure 5;

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Figure 7 is a partial section of another modified joint;

Figure 8 is an enlarged view of Figure 7;

Figure 9 is a partial view of the lower portion of a sealed collapsible tube;

Figure 10 is a section on line 10-10 of Figure 9 showing the bottom seal;

Figure 11 is a partial View of the lower portion of a sealed tubular bottle or other container;

Figure 12'is a section on line 12--12 of Figure ll; and

Figure 13 is a section like Figures 2 and 6 showing the top surface of the head piece extending substantially hori- Zontal with respect to the vertical body wall.

Referring to Figure l, the conventional mold has the mandrel 10 provided at its upper end with a substantially frusto-conical mold head section 11 terminating in a neck mold section 12. As shown, the outer surface of the head section 11 is curved in vertical section as at 13. The neck section 12 terminates in a mold guide pin 14. The female mold member is indicated at 15 and has a recess provided with an internal, generally frusto-conical surface 16 curved in vertical section and substantially conforming to the opposed outer surface of the head 11. The said recess16 terminates in a thread-forming neck section 17 cooperating with the mandrel neck section 12 and also having a recess 18 for receiving the mandrel guide pin 14.

The preformed thermoplastic tubular body 19 is held fixed, as shown, between the mandrel 11 and the female mold member 15 by friction or any simple stop means. The tubular body 19 has its upper end 2i) extended to expose its innerwall surface, i. e., so as to be free of the adjacent opposed outer surface 13 of the head 11. The exposed or free portion of the upper end 2) abuts the adjacent opposed inner curved surface 16 of the female mold member 15', both vertically, as at 21, and on an inwardly extending curve, as at 22. The longitu: dinal extent of the exposed portion 2th, i. e., the amount of its free surface relative to the opposed surface 13 of the mandrel 11, is controlled so as to provide the substantially vertical and inwardly curved portions Zit-22, respectively of any desired length. Thus, the body of the tubular member may, in this regard, have the length of the exposed portion 21-22 varied, as desired, The important consideration is that there be no wrinkles in the final container by reason of the extension 2Q and that the same have a substantially vertical portion 21 and an inwardly curved portion 22 so as to form a smooth, continuous mold surface, on the one hand, and, on the other, a smooth, continuous overlapping outer surface for the container at the point where the head piece is vfused and united to the end of the tubular body, as shown, i. e., at the top surface S and side S' of the container.

Referring again to Figure 1, the openings 23 in the mold element 15 are provided to allow the injection of molten plastic into the mold space provided between the opposed surfaces 13 and 16 of the mandrel 11 and female mold member 15, respectively. As mentioned above, the exposed extension 2i) of the thermoplastic tubular body 19 also forms a part of the female mold.

In this manner, the plastic injected through the openings 23 of the female member fills the mold space provided as above to form an injection-molded head piece or top 24, which is generally frusto-conical but may be of any desired shape, e. g., flat, as shown in Figure 13. Since the plastic extension 20 of the tubular body forms a part of the outer wall of the mold space, the hot molten plastic fuses the same at its inner face to form an integral union and joint area, as shown. In this manner, the extended portion 20 with its vertical portion 21 and its inwardly curved portion 22 overlies the top and side of the head piece produced by injection molding and merges with the material thereof along the lower 3 narrow marginal area of the head Figure 1.

Consequently, a strong, integral joint is formed which is continuous peripherally and also vertically, when viewed in section. This fused joint area constituted by the overlying merged material or band of the lower margin H of the head piece and the upper band or narrow margin T of the tubular body, provides resistance to both axial and radial strain and rigidies the container at a vital point so as to avoid distortion of its shape in handling or iilling. In brief, the seal embraces the head piece and body substantially vertically and at an angle to the vertical, as seen in Figures 1 to 8 and 13.

Referring to Figure 5, the female mold has a Vcircular recess 27 which produces a circular, smooth and rounded, raised, overlapping ring portion 28, as shown in Figure 6. In this gure, the neck mold section has different thread-formiiig portions, as shown. Also, the frustoconical surface 13 of the mandrel is substantially straight in vertical section, as shown.

In Figure 7, the joint area 29 is on a continuous curve, as shown in enlarged detail in Figure 8, and includes the continuous, vertical and inclined fused joint portions.

In Figures 9 and l0, the numeral 30 indicates a fused joint at the bottom of the tapering tubular body 19, which here is in the forni of the usual tapered collapsible tube. This seal is formed after the tube has been lled through the bottom.

Figure 11 shows the fused joint 31 sealing the bottom of a bottle of uniform diameter throughout.

Top filling or bottom filling may be employed, it being noted that in either case, the body of the tapered tube or cylindrical bottle is devoid of external projections which would interfere with handling, packing or printing.

Upon reference to Figures 1 to 8 and 13, it will be noted that a narrow band of the material of the body of the container and a narrow band of equal width of the head piece are integrally united in overlapping relation in the fused joint, which is indicated as a whole by the numeral I, and that this joint area embraces, as stated, both the top and side of the container within the area of said respective band portions at the upper end of the container.

The same numerals in the several views represent the same parts.

In each of the various constructions described above, the body, the head piece and the bottom are formed of a conventional thermoplastic material, such as polyethylene, but, as explained, other polymeric thermopiece, as shown in` 4 tively greater thickness than the body wall 19 and this is preferred, there are instances where the thickness of the head piece may be less or equal to the thickness of the body wall.

The manner in which the surface of the head piece merges with the body wall 19 on the interior of the container will vary from the gentle slope 32 shown in Figures l, 2, 3 and 13 to a sharp angle, as shown at 33 in Figures 5 and 6, or an abrupt angle or step 34, as in Figure 4, or a less abrupt angle or step than at 34, as shown at 35 in Figures 7 and 8. Exteriorly the upper end of the overlapping portion 22 may merge into the outer surface of the head piece in various Ways but, in all cases, the exterior of the joint area is smooth and has a nice appearing ush nish, as shown at 36 in the several views.

I claim:

l. A container of thermoplastic material having a tubular body portion and a head portion integrally fused thereto, said head portion provided with a narrow stepped marginal area overlapping and fused with a narrow band area of the body portion at one end of the saine on the outer and top surfaces of the head portion to form a joint area, said joint area comprising a continuous circumferential downwardly extending portion of the stepped margin of the head portion disposed inside ot the body wall and the narrow marginal band of the body wall extending partially over the top surface of the head portion.

2. A container according to claim 1 wherein the head portion is frusto-conical and extends above the tubular body portion, the narrow marginal band of the body l portion extending partially over and fused to the adjacent top sui-face of the head portion at the base of the frusto-conical head portion and said continuous, circumferential, downwardly extending portion of the head portion being fused to the adjacent Wall surface of the tubular body below said last-mentioned fused area.

3. A container according to claim 2 wherein the outer surfaces of said head portion and said body portion merge into a smooth, substantially uninterrupted surface on the outside surface of the frustO-conical head portion continuing throughout the outer Surface of the joint area.

4. A container according to claim 3 wherein the material of the frusto-conical head portion is continued at its apex into and terminates in a cap-receiving portion.

References Cited in the le of this patent UNITED STATES PATENTS 

